The present invention relates particularly to an operation microscope for use in a surgical operation of a fine portion in cranial nerve surgery, and the like.
In conventional cranial nerve surgery, to absolutely perform a delicate operation, an operation microscope for stereoscopically enlarging an image of a portion being subjected to the operation has been utilized in many cases. Furthermore, in recent years, to certainty carry out an operation, endoscope observation is performed in a conventional operation concurrently with the operation microscope. Therefore, it has been desired that an operation microscope observation image and an endoscope observation image can be simultaneously observed in a field of view of the operation microscope. Moreover, it has also been desired that not only the operation microscope observation image, endoscope observation image, and nerve monitor information but also preoperative CT and MR images can be simultaneously observed during the operation.
Examples of a known prior art include Jpn. Pat. Appln. KOKAI Publication Nos. 9-56669, 11-258514 and Published Japanese Patent No. 11-288328. In these publications, at least a part of an observation image of a second observation means is displayed as an in-field display image in a field of the microscope observation image as first observation means for observing the operative portion. For example, a liquid crystal filter is used to shield the microscope observation image, an image is projected into the shielded portion, and the observation image of the second observation means can be displayed in an arbitrary position in a field of the microscope observation image. Thereby, a dead angle portion which cannot be observed with the microscope observation image and a state inside a body tissue can be recognized by the observation image of the second observation means.
However, in the aforementioned prior art, since the size or the like of the in-field display image displayed in the field of the microscope observation image cannot be freely changed, the image display itself can possibly interfere with the orientation handling of endoscope observation. Furthermore, since the observation image of the second observation means cannot be observed as a large image, there is a problem that the observation image of the second observation means cannot be as finely observed as the large image.